Hearing Loss

What is Hearing Loss?

Hearing loss is the partial or complete inability to hear sounds. Loss of hearing can happen to anyone, at any age and it affects millions of people around the world. It can range from a mild hearing loss to severe or profound in intensity.

The impact of hearing loss can be alarming. It can interfere with one’s ability to communicate with others and understand the speech of others in various situations. 

Hearing Loss vs. Deafness

A person whose hearing thresholds exceed normal thresholds of 20 dB in both ears is considered to have hearing loss. It could vary from mild to profound levels in degree. 

Deafness is best described in a person having difficulty in speech recognition even when amplification is provided by an assistive hearing devise.

Types of Hearing Loss

The three basic categories of hearing loss are Conductive Hearing loss, Sensory neural Hearing loss and Mixed Hearing loss. The ear is broadly divided into three parts- the outer, middle and the inner ear. 

• Conductive hearing loss occurs in the outer or middle ear where the sound waves are not able to reach the inner ear. Conductive hearing loss is commonly seen in children who may have recurrent ear infections or insert a foreign object into their ear canal.
• Sensory neural hearing loss is one of the most common types of hearing loss that affects the inner ear, which can be a result of aging, exposure to noise, certain drugs or inherited conditions. 
• Mixed hearing loss is best described as a combination of both conductive and sensory neural hearing loss. 

Categories of Hearing Loss

• Prelingual vs Post lingual: A prelingual hearing loss occurs before a child acquires language and post lingual hearing loss occurs after a child has learned and understood some language.
• Unilateral vs bilateral: Unilateral refers to hearing loss in one ear while bilateral refers to hearing loss in both ears.
• Symmetrical vs asymmetrical: Symmetrical is when the severity and pattern of hearing loss is the same in both ears while they may be different in both the ears in asymmetrical hearing loss.
• Progressive vs Sudden: progressive refers to the deterioration in hearing over a period of time. Sudden refers to a quick fall in hearing thresholds within a very short period of time.
• Fluctuating vs Stable: Hearing loss that shows minimal or negligible changes over time is considered stable while hearing thresholds that keep going up and down over time is known to be fluctuating in nature.
• Congenital vs Acquired: If a child is born with hearing loss it is congenital. If the loss occurs after birth, during developmental or later years it is said to be acquired.

Degree of Hearing Loss/Levels of Deafness

Degree of hearing loss is based on how loud a sound needs to be for a person to hear it. The term dBHL describes hearing loss in decibels. Degree of hearing loss ranges from-

• MILD- 21- 40 dB- Difficulty hearing and understanding quiet/soft conversations, especially situations with a lot of background noise (restaurants, classrooms, etc.)
• MODERATE- 41- 55 dB- Difficulty understanding speech, higher volume levels are required for hearing TV and radio
• MODERATELY SEVERE- 56-70 dB- Speech has to be louder than normal, group conversations are difficult
• SEVERE – 71-90 dB- Difficulties with speech, comprehension becomes impossible without amplification
• PROFOUND- 91 dB and greater- Amplified speech or devices are still ​​​difficult ​or impossible to hear and understand

Common Symptoms of Hearing Loss

Here are some warning signs of hearing loss:

• Often asking people to repeat themselves
• Having trouble following a conversation, especially while talking on the telephone or in a noisy environment
• Thinking that people are mumbling
• Turning up the TV/music volume beyond usual levels
• Difficulty in hearing certain high-pitched sounds, like birds singing

Symptoms of Hearing Loss in Babies and Children

• When the baby does not startle to loud noises
• Baby does not turn to the source of a sound after 6 months of age
• Do not acquire first words like “mamma” by age one
• Do not react when you call out their name
• Children are slower to learn to speak than other children their age
• Develop unclear speech
• Do not follow commands or instructions and use gestures to communicate
• Turn up the TV volume

Causes of Hearing Loss 

The most common reasons for a hearing disability could be one of the following:

• Genetic abnormality or caused at birth
• Hearing loss due to natural aging process
• Middle ear abnormalities
• Intake of medications that might affect the ear
• Exposure to sudden loud noise or impact
• Head injury or trauma
• Continuous exposure to noise over many years

How is Hearing Loss Diagnosed?

Diagnosing hearing loss involves the following

• Physical examination- the audiologist looks for possible causes related to structural changes, ear wax, foreign body, infections etc
• Screening test- A simple test performed for each to see how one reacts to sounds
• Diagnostic test-Audiometric tests-  an audiologist, performs a series of thorough tests. Sounds and words are directed through earphones to each ear. Each tone is repeated at low levels to find the quietest sound you can hear.

Common Hearing Tests (Adults and Children)

• Otoscopic evaluation: It is the initial step, a basic routine procedure carried out with a tool known as otoscope to visualize and examine the ear canal and eardrum.
• Pure Tone Audiometry: It is the main diagnostic procedure used to assess and identify the type degree and configuration of hearing loss.
• Play audiometry: Used for paediatric population where responses are elicited by engaging the child in play activity.
• Conditioned audiometry: Where the child is conditioned to respond upon hearing the sound signal.
• Visual reinforcement audiometry: Used in children where visual stimuli are used when child responds to signal.
• Behavioral Observation Audiometry: Used in very young children, difficult to test population or malingering clients where clinicians look for behavioral responses to the provided sound signal. 
• Tymapanometry/ immmitance audiometry/ impedance audiometry: Tests to identify the condition of the middle ear.
• Speech Audiometry: Tests how loud speech needs to be for the client to hear it and checks how the client understands and distinguishes different speech sounds Results of speech audiometry helps in selection and efficiency of hearing aids.
• Brainstem Evoked Response Audiometry BERA/ABR: Identifies hearing thresholds in specific frequency range. 
• Oto Acoustic Emissions OAE: Tests the functioning of outer hair cells and detection of hearing loss. 

Hearing Loss Treatment 

Conductive hearing loss:

• Medication and Surgery. Some types of hearing loss can be treated with surgery. For repeated infections that cause fluid in the ear, a care provider might put in small tubes that help ears drain and provide appropriate medication.

Sensorineural hearing loss:

• Hearing aids. If hearing loss is from damage to the inner ear, a hearing aid can be helpful. A hearing specialist, known as an audiologist, can talk about how hearing aids can help and what kinds there are. Audiologists also can fit you with a hearing aid.
• Cochlear implants. When a regular hearing aid isn't likely to help much, a cochlear implant might be an option.

Mixed Hearing loss: A combination of medical treatment and hearing aids.

Factors that Lead to Hearing Loss

• Aging -is one of the most common factors that affect hearing. Usually occur due to aging of hair cells in the inner ear.
• Loud noise-exposure to loud noise as in factories or traffic for extended periods of time can cause damage to the ears leading to hearing loss.
• Hereditary- genetic inheritance as in conditions like otosclerosis may affect the middle ear thereby leading to hearing loss
• Medicines-intake of ototoxic drugs for extended period could potentially damage hearing

How Can I Prevent Hearing Loss?

• Do not expose yourself to loud noise levels or loud music for extended periods of time
• Using ear protective devices in a noisy environment
• Cautious o]use of medication
• Leading a healthy lifestyle
• Maintain aural hygiene
• Get periodic hearing tests done
• Early intervention- Hearing loss can affect a child’s ability to develop speech, language, communication and social skills. The earlier a child who is hard-of-hearing starts getting services, the more likely the child's speech, language, and social skills will reach their full potential.

Preparing for Your Appointment

What happens typically during an audiological examination is detailed below:

• Detailed discussion about your work and lifestyle
• Talking about hearing difficulties, your listening needs and your medical history.
• An examination of your ears.
• A detailed hearing test.
• Discussion of results and future steps

Concluding Notes

The different degrees and types of hearing loss and hearing aid requirement have been discussed in details. It is important to understand with the help of an audiologist what kind of hearing aid is best suitable for you. Try to keep regular follow ups with your hearing care specialist to track further developments in your hearing ability. For more details, contact us at-